Cette thèse est motivée par diverses questions qui se posent quant à l’utilisation de l’isolation sismique dans l’industrie nucléaire. À la différence de la grande majorité des travaux antérieurs sur l’isolation sismique en générale et l’isolation mixte en particulier, qui portent principalement leur intérêt sur la réponse de la structure isolée (déplacements relatifs, accélérations maximales des étages, etc.), une grande partie de ce travail est consacrée au comportement des équipements, par le biais de l’étude des spectres de plancher. L’objectif principal est de diminuer la déformation des isolateurs sans amplification de la réponse des modes supérieurs, qui peut apparaître sous certaines conditions et qui peut être une source de sollicitation des équipements. Pour ce faire, des alternatives aux appuis parasismiques couramment utilisés sont explorées. Il s’agit des combinaisons d’un appui à faible amortissement avec un élément de Maxwell (isolateur de relaxation) ou avec un amortisseur hydraulique semi-actif (système d’isolation mixte). L’élément de Maxwell se comportant comme un amortisseur à basse fréquence et un ressort de faible rigidité à haute fréquence permet de satisfaire l’objectif souhaité. En ce qui concerne les systèmes d’isolation mixtes, trois techniques de contrôle semi-actif sont proposées. Afin d’améliorer la performance du contrôle, une attention particulière a été donné à la prise en compte de l’excitation sismique et des caractéristiques de l’amortisseur lors de la conception du contrôleur est focalisée. Les analyses numériques confirment l'efficacité de ces systèmes. En vue de l’utilisation de ces méthodes pour de structures réelles, certains aspects pratiques comme, par exemple, l’observation du système, les effets de la réduction du modèle utilisé par le contrôleur ou du temps de retard sur la performance du contrôle, ainsi que le contrôle d’un ensemble de plusieurs dispositifs semi-actifs redondant, sont, également, abordés. / This thesis is motivated by various questions that arise regarding the use of base isolation in the nuclear industry. Unlike the majority of previous work on base isolation in general and mixed isolation in particular, which focus mainly on the response of the isolated structure (interstorey drifts, maximum accelerations of floors, etc.), this work focuses on the behavior of equipment, through the study of floor response spectra. The main objective is to reduce the deformation of the isolators without amplification of the response of the higher modes, which may appear under certain conditions and which can be a source of equipment solicitation. To this end, alternatives to the commonly used base isolators are explored. These are combinations of a low damping rubber bearing with a Maxwell element (relaxation isolator) or a semi-active hydraulic damper (mixed base isolation system).Maxwell element behaves like a damper in low frequency and as a low stiffness spring in high frequency. Hence it meets the above objectives. . Regarding isolation systems, three semi-active control techniques are proposed. In order to improve the performance of the control, the seismic excitation and the characteristics of the damper are taken into account in the design of the controller. Numerical analyzes confirm the effectiveness of these systems. Having in mind implementation of these methods to real structures, some practical aspects such as, observation of the system, effects of model reduction, considered by the controller, or time delay on the control performance, as well as the control of a set of redundant semi-active devices, are also studied.

Carregamentos transientes termo hidráulicos do tipo Steam Hammer são eventos comuns em sistemas de tubulações de vapor com grandes potenciais de catástrofes em plantas de geração de energia. Uma vez iniciado o evento, ondas de pressões são geradas com amplitudes, geralmente, de grande magnitude ocasionando altas pressões no sistema, ruídos, deformações, fadiga, com possibilidade de danos materiais e econômicos e em casos extremos fatalidades. Os procedimentos da indústria para análise deste tipo de sistema consistem realização de análises estáticas equivalentes ou análise de espectro de resposta com carregamentos caracterizados por meio de métodos analíticos baseados em hipóteses simplificadoras do fluido e fluxo. Neste trabalho é proposta a analise de sistema de tubulações por meio do método de integração numérica com superposição modal e carregamento caracterizado por método numérico com base no método das características. Comparações foram efetuadas entre os resultados obtidos pela metodologia proposta e os procedimentos da indústria, demonstrando que, dado ao alto grau de conservadorismo, os procedimentos da indústria acarretam em superdimensionamento de estruturas e tubulações ocasionando custos adicionais de projeto, sendo a otimização do projeto obtida aplicando-se a metodologia proposta no trabalho. / Steam Hammer is a common transient thermo hydraulic event in steam piping systems with potential to cause serious damages in power generation plants. It generates pressure waves, generally of great amplitude and magnitude, causing high pressures in the system, associated with noise, with possible material and economic damages and, in extreme case, even fatalities. Industry procedures for analysis of these events consists of performing equivalent static analysis, or response spectrum analysis, with transient loadings calculated by analytical methods based on assumptions of fluid and flow. This paper proposes a new methodology for the piping system analysis by the numerical integration method with modal superposition and transient loadings calculated by a numerical method based on the method of characteristics. Comparisons were made between the results obtained by the proposed methodology and the stablished industry procedures, confirming that, due to the high degree of conservatism, industry procedures can lead to additional cost to the design, with the optimization of the design being obtained by applying the methodology proposed in this paper.

Carregamentos transientes termo hidráulicos do tipo Steam Hammer são eventos comuns em sistemas de tubulações de vapor com grandes potenciais de catástrofes em plantas de geração de energia. Uma vez iniciado o evento, ondas de pressões são geradas com amplitudes, geralmente, de grande magnitude ocasionando altas pressões no sistema, ruídos, deformações, fadiga, com possibilidade de danos materiais e econômicos e em casos extremos fatalidades. Os procedimentos da indústria para análise deste tipo de sistema consistem realização de análises estáticas equivalentes ou análise de espectro de resposta com carregamentos caracterizados por meio de métodos analíticos baseados em hipóteses simplificadoras do fluido e fluxo. Neste trabalho é proposta a analise de sistema de tubulações por meio do método de integração numérica com superposição modal e carregamento caracterizado por método numérico com base no método das características. Comparações foram efetuadas entre os resultados obtidos pela metodologia proposta e os procedimentos da indústria, demonstrando que, dado ao alto grau de conservadorismo, os procedimentos da indústria acarretam em superdimensionamento de estruturas e tubulações ocasionando custos adicionais de projeto, sendo a otimização do projeto obtida aplicando-se a metodologia proposta no trabalho. / Steam Hammer is a common transient thermo hydraulic event in steam piping systems with potential to cause serious damages in power generation plants. It generates pressure waves, generally of great amplitude and magnitude, causing high pressures in the system, associated with noise, with possible material and economic damages and, in extreme case, even fatalities. Industry procedures for analysis of these events consists of performing equivalent static analysis, or response spectrum analysis, with transient loadings calculated by analytical methods based on assumptions of fluid and flow. This paper proposes a new methodology for the piping system analysis by the numerical integration method with modal superposition and transient loadings calculated by a numerical method based on the method of characteristics. Comparisons were made between the results obtained by the proposed methodology and the stablished industry procedures, confirming that, due to the high degree of conservatism, industry procedures can lead to additional cost to the design, with the optimization of the design being obtained by applying the methodology proposed in this paper.

[pt] Estuda-se a consideração de comportamento inelástico do material na geração de espectros de resposta de projeto. Para tanto, trabalha-se sobre um sistema secundário simplificado acoplado a um pórtico de cinco andares com características dinâmicas ajustadas para modelar um sistema principal real, de uma usina nuclear. Faz-se um estudo paramétrico sobre estes sistemas acoplados onde são variados os parâmetros: fator de escoamento, a intensidade da excitação e o nível de amortecimento. É proposto um fator de dutilidade global formulado em termos de trabalho externo realizado sobre o sistema secundário. São obtidos espectros de dutilidade e de resposta. A análise de tais espectros fornece informações sobre o desempenho do sistema secundário e seus suportes e conclui por fatores de transposição entre os espectros elástico e inelástico. Propõe-se metodologia para obtenção de espectros de resposta elásticos e inelásticos que levam em conta o acoplamento entre os sistemas principal e secundário, o movimento relativo dos suportes e o compromisso probabilístico entre as ordenadas do espectro e a sismicidade da região expressa em termos de uma função densidade de espectro de potência objetivo para a aceleração do terreno. Um exemplo de obtenção de espectros de resposta acoplada de projeto uniformemente provável inelástico é apresentado. / [en] The authors concern includes two main points in the subject of design response spectra generation for secondary systems in nuclear power plant structures: the consideration of inelastic behavior in the secondary systems materials and the production of uniformly probable design response spectra. One works with a previously developed secondary system model attached to primary structure model tuned to the frequency range of a nuclear power plant building. A global ductility factor is formulated relating the plastic to the overall work done by the seismic external forces on the secondary system. This factor together with a particular definition of the yielding factor allows one to determine elastic to inelastic spectrum transpose factors. A methodology is proposed to generate uniformly probable coupled response spectra for multiply supported inelastic secondary systems. The seismic excitation is prescribed by a target power spectrum density function of the ground acceleration and an internal pressure condition is added to the seismic action. Examples illustrate the application of this proposed methodology.

[pt] Os resultados apresentados referem-se à investigação dos mecanismos de interação entre dois sistemas vitais às usinas nucleares, ou seja: os sistemas Principal (SP) e o Secundário (SS). Estes mecanismos são avaliados por meio de sua influência nos espectros de resposta, em pontos da estrutura passíveis da existência de suportes das linhas de tubulação - SS. São usados dois tipos diferentes de análises para a geração dos espectros de resposta: a primeira não considera a interação dos sistemas e a segunda avalia esta interação com a introdução, em cada ponto de suporte no SP, de um S1GL com suportes únicos ou com multi- suportes. As respostas estruturais são obtidas por integração direta da equação de movimento do sistema sujeito a dois acelerogramas simultâneos, nas direções horizontal e vertical. Os resultados são analisados e comparados para identificação das principais tendências das análises e esclarecimento dos efeitos envolvidos. Estuda-se, também, a importância de não- linearidades concentradas nos suportes da tubulação, tendo- se em vista o nível sísmico a que as centrais nucleares brasileiras estão sujeitas. / [en] The results presented in this work refer to the investigation of the mechanics of the interaction between two important systems of nuclear power plants, i.e.: the Primary (PS) and Secondary (SS) systems. The influence of these effects on the response spectra is studied, in convenient points of the structure where could exist pipeline (SS) supports. Two different approaches are used to generate the response spectra: the first neglects the interaction between the two systems and the second considers this interaction by the addition, to every support point on the PS, of a single-supported or multi-supported SDOF system. The structural responses are obtained by the direct integration of the Primary System equations of motion subjected to two simultaneous design acceleration time-histories, in the horizontal and vertical directions. The results are analyzed and compared to identify the general trends of the solutions obtained by the two types of analysis, and to detect their effects on the SS response. The study is concerned, also, with the importance of nonlinearities concentrated in the pipeline supports; in the case of the Brazilian nuclear power plants. / [es] Los resultados presentados se refieran a la investigación de los mecanismos de interacción entre de los los sistemas Principal (SP) y el Secundario (S) de las plantas nucleares. Estos mecanismos son evaluados por medio de su influencia en los espectros de respuesta, en puntos de la extructura donde es posible(pausibles) la existencia de soportes de las líneas de tuberías - S. Son usados dos tipos diferentes de análisis para la generación de los espectros de respuesta: la primera no considera la interacción de los sistemas y la segunda evalúa esta interacción con la introdución, en cada ponto de soporte en el SP, de un S1GL con soportes únicos o con multisoportes. Las respuestas extructurales son obtenidas por integración directa de la ecuación de movimento del sistema sujeto a dos acelerogramas simultáneos, en las direcciones horizontal y vertical. Se analizan los resultados y se comparan para identificar las principales tendencias del análisis y esclarecer los efectos involucrados. Se estudia además, la importancia de no linealidades concentradas en los soportes de la tubería, teniendo en vista el nível sísmico a que las centrales nucleares brasileras están sujetas.

Nous nous intéressons aux méthodes de contrôle de vibrations de modèles réduits de structures à n degrés de liberté, sismiquement isolées au niveau de la base par des systèmes d'isolation mixte.Le mouvement provoqué par une sollicitation sismique horizontale a lieu dans le plan vertical.Nous avons construit un problème de contrôle semi-actif de systèmes incertains soumis à des perturbations inconnues, mais bornées. Dans le langage de l'automatique, il s'agit d'un problème d'atténuation de perturbations.Le résultat principal de cette thèse porte sur la construction d'une version modifiée des résultats de Leitmann et de ses collaborateurs sur la stabilisation de systèmes non linéaires incertains. Le théorème proposé repose sur une loi de commande par retour d'état qui assure en boucle fermée les propriétés de "uniform boundedness" et "uniform ultimate boundedness".En particulier, il peut être appliqué à la résolution de problèmes de contrôle semi-actif, qui sont actuellement traités en génie parasismique.L'objectif du contrôle est d'améliorer le comportement (i.e. la réponse) de structures isolées pour faire face aux perturbations externes, c'est-à-dire les séismes. Plusieurs points différencient notre problème de la majorité que l'on trouve dans la littérature: (i) on ne s'intéresse pas seulement à la protection de la structure isolée, mais aussi aux équipements situés à l'intérieur de la structure, et (ii) au lieu d'utiliser des indicateurs de performance habituels exprimés en termes de déplacement relatif de la base versus des accélérations absolues des planchers, nous utilisons uniquement le spectre de plancher en pseudo-accélération, comme il a été proposé dans des travaux précédents par Politopoulos et Pham. Ce travail est une tentative d'utiliser explicitement les spectres de plancher comme critère de performance.Concernant la procédure d'application, plusieurs étapes intermédiaires ont été détaillées:(i) modélisation de signaux sismiques;(ii) réglage des paramètres de la loi de commande utilisant la théorie des vibrations;(iii) validation et test du comportement en boucle fermée à travers des simulations numériques: pour des raisons de simplicité, on se limite au cas n=2.Cette procédure peut être utilisée sur des structures en industrie nucléaire, mais aussi en génie civil.D'autres sujets traités incluent une tentative d'utiliser les outils temps-fréquence, et en particulier la distribution de Wigner-Ville, pour la synthèse de lois de commande, en espérant pouvoir mieux contrôler les composants transitoires des signaux de perturbation (les entrées) et des variables d'état (les sorties). / Vibration attenuation control designs are proposed for reduced plant models consisting of n-degree-of-freedom base seismically-isolated structures (i.e., a specific type of earthquake-resistant design), modeled by uncertain nonlinear systems and subjected to one-dimensional horizontal ground acceleration (i.e. the earthquake signal), treated as unknown disturbance but assumed to be bounded.In control systems literature, this is a perturbation attenuation problem.The main result of this PhD is the development of a modified version of Leitmann and co-authors' classical result on the stabilization of uncertain nonlinear systems. The proposed theorem consists of a bounded nonlinear feedback control law that is capable of ensuring uniform boundedness and uniform ultimate boundedness in closed-loop. In particular, it can be applied to solving semi-active control design problems, which are currently dealt with in earthquake engineering.The control objective is to improve the behavior (i.e. response) of mixed base-isolated structures to external disturbance, namely earthquakes. What differentiates our problem from the majority to be found in the literature is that: (i) attention is being paid to the protection of equipment placed inside the structure an not only to the structure itself; (ii) instead of using regular performance indicators expressed in terms of relative base displacement versus floors accelerations, we use solely the pseudo-acceleration floor response spectra, as it was proposed in previous recent works by Politopoulos and Pham.Actually, this work is an attempt to explicitly use floor response spectra as performance criterion.Concerning the application procedure, some of the topics that were detailed are:(i) modeling of earthquake signals;(ii) tuning of control law parameters based on vibration theory;(iii) validation and testing of the closed-loop behavior using numerical simulations: for simplicity reasons, we take n=2.This procedure can be used on structures of both nuclear industry as well as civil engineering.Other topics include an attempt to using time-frequency concepts and in particular the Wigner-Ville distribution to the control law design procedure, in order to better control transitory components of both perturbation (the input) and state variables signals (the output).

[pt] A análise de estruturas de sistemas secundários sujeitos a cargas sísmicas é um assunto em aberto e especial no projeto de instalações industriais. Dois pontos particulares atraem a atenção dos especialistas no esforço a caminho de um projeto mais realista, abrangente e econômico: a interação das propriedades dinâmicas entre os sistemas principal e secundário e a quantidade de dutilidade do sistema secundário que pode ou deveria ser considerada no projeto. Está muito evidente nesse estágio que a decisão do projetista tem de ser bem assessorada porque dependendo das circunstâncias os resultados finais podem mostrar muitas surpresas. O contexto das experiências nesse assunto, na PUC-Rio, inclui uma série de iniciativas. Entre elas, se pode dar especial menção às seguintes: o estudo e proposta de uma metodologia para desenvolver um espectro de resposta acoplada (Valverde, 1998); o desenvolvimento de um modelo de sistema secundário simplificado: com vários graus de liberdade, linearelástico, formado por elementos tubulares, conexões e suportes com molas (Castañaga, 1998); a introdução do efeito inelástico nos elementos tubulares e suportes do sistema secundário simplificado e definição de um fator de dutilidade global do sistema para relacionar, qualitativa e quantitativamente, o espectro de resposta acoplada do sistema secundário simplificado, sob comportamento elástico e inelástico (Sampaio, 2003). Agora, um outro avanço é incorporado, com o presente estudo, o da influência de cargas estáticas nos elementos devidas à pressão interna e variação de temperatura, nessas relações do espectro de resposta elástica e inelástica. Também é feita uma comparação dos espectros de resposta elástica e inelástica do sistema secundário acoplado e não acoplado. Espectros médios aproximados para a resposta inelástica acoplada do sistema secundário simplificado são também propostos. / [en] The analysis of secondary structure systems to seismic loads is a special and open subject in the design of industrial installations. Two particular points attract specialist attention and effort on the way of a more realist, comprehensive and economical design: the dynamical properties interaction between the secondary and principal systems and the amount of the secondary system ductility which can or should be considered in the design. It is very clear at this stage that the designer decision has to be well advised because depending on circumstances the final results may show very surprising. The context of experiences on this subject, at PUC-Rio, includes a series of initiatives. Among them, one may to give special mention to the following: the study and proposal of a methodology to develop a coupled floor response spectrum (Valverde, 1998); the development of a simplified secondary system model: multidegree, linear-elastic, tubular elements and connexions and spring supports (Castañaga, 1998); the introduction of inelastic action in the tubular elements and supports of the simplified secondary system and the definition of a system overall ductility factor to relate, qualitative and quantitatively, the simplified secondary system coupled response spectrum under elastic and inelastic behavior (Sampaio, 2003). Now, another advancement is enhanced with this study on the influence of element static loads due to internal pressure and temperature variation on these elastic and inelastic response spectrum relationships. Comparison also is made into coupled and uncoupled secondary system elastic and inelastic response spectra. Approximated medium response spectra for the inelastic coupled response of a simplified secondary system are also proposed.

Construction of structural computational model of the tank with fluid using program package ANSYS based on the Finite Element Method. Solve eigen-vibration of the tank with or without effects of fluid. Application of Euler and Lagrange method for modeling fluid. Solve seismic response using response spectra. Verify of the tank in accordance to EC 3 and EC8.

The dissertation deals with selected issues in the field of the calculation of the response of building structures which are excited with dynamic non-stationary displacement loading of its ground. Seismic load has been assumed. Procedures, how to work with seismic records with respect to the accuracy of dynamic calculations, how to modify the response spectrum to ensure the reliability, how to generate synthetic accelerogram requiring more accurate response, are recommended. Synthetic akcelerogram has been generated by own approaching, which has been used as the excitation function in the experimental seismic testing of autoclaved concrete brick building in model scale. Response values of motion in the measured points of the experiment were compared with the linear and nonlinear dynamic calculations by using the finite element method models. Different levels of detail of the numerical models have been used. The shear wall behaviour has been modelled by using constitutive models with brittle failure as well as using of non-linear interaction interface with possible delamination between the masonry bricks. The behaviour of the mathematical model of wall systems has been calibrated with respect to the measured data at shear wall experiments in real and model scale of walls.